Doubling the Lifetime of Polymer Electrolyte Membranes: Monolayer Graphene Gas Barriers

Abstract

Polymer electrolyte fuel cells (PEFCs) are an important contributor to the hydrogen economy, yet their limited lifetime remains a critical barrier to widespread adoption. A primary mode of cell failure is thinning of the polymer electrolyte membrane (PEM), eventually leading to pinhole formation. This is caused by peroxide radicals which arise due to gas crossover. Here we report a simple strategy to double the lifetime of PEFCs by embedding an atomically thin graphene interlayer within a 10 µm thick PEM. The resulting Nafion-Graphene-Nafion (N|G|N) architecture decreases hydrogen crossover current density by ~35%, without compromising ionic conductivity or maximum power density. Accelerated open circuit voltage (OCV) holding tests show that this leads to a doubling of PEFC lifetime, whilst post-mortem analysis confirms that the rate of membrane thinning is dramatically reduced. This work establishes graphene-based barriers as a transformative approach to extend the lifetime of electrochemical devices by suppressing chemical degradation, enabling the development of thinner and more durable membranes whilst advancing the development of cost-effective electrochemical systems.

Keywords: polymer electrolyte membrane fuel cell, Hydrogen, Graphene, crossover, Durability, membrane